I was curious if there was an all inclusive site that helped to plan
more than just the audio/video equipment, but also location of
speakers, decor, acoustic panels for the wall, cabling, other things
like this.

Specifically, I would also be interested if anyone has used acoustic
panels before and what their experience has been.

I made my own acoustic panels by taking acoustic ceiling tiles and covering
them with batting and material. You can choose fabrics that compliment your
decor and it was pretty cheap. All you need is some scissors and a hot glue
gun.